What Are Periods & Groups In The Periodic Table?

The video tutorial explains the periodic table's structure, focusing on periods and groups. Periods are horizontal rows where elements share the same number of energy shells, while groups are vertical columns where elements have the same number of valence electrons. The tutorial highlights how these arrangements help predict element properties and reactivity. Group 7 elements, such as fluorine and chlorine, are used as examples to illustrate these concepts.

What is the main characteristic shared by elements in the same period of the periodic table?

• They have the same number of energy shells.

• They have the same number of protons.

• They have the same atomic mass.

• They have the same number of neutrons.

What do elements in the same group of the periodic table have in common?

• They have the same atomic mass.

• They have the same number of valence electrons.

• They have the same number of energy shells.

• They have the same atomic number.

Why are valence electrons important for elements?

• They are responsible for the element's mass.

• They determine the element's color.

• They are involved in chemical reactions and bonding.

• They define the element's state of matter.

Which of the following elements is in Group 7 of the periodic table?

• Chlorine

• Carbon

• Oxygen

• Sodium

How do the properties of elements in Group 7 change as you move down the group?

• They have fewer valence electrons.

• They become less reactive.

• They have more energy shells.

• They become more metallic.